Finally we have a high-level admission that there is no threat of a global Aids pandemic among heterosexuals. After 25 years of official scaremongering about western societies being ravaged by the disease – with salacious, tombstone-illustrated government propaganda warning people to wear a condom or "die of ignorance" – the head of the World Health Organisation's HIV/Aids department says there is no need for heterosexuals to fret.

Kevin de Cock, who has headed the global battle against Aids, said at the weekend that, outside very poor African countries, Aids is confined to "high-risk groups", including men who have sex with men, injecting drug users, and sex workers. And even in these communities it remains quite rare. "It is very unlikely there will be a heterosexual epidemic in countries [outside sub-Saharan Africa]", he said. In other words? All that hysterical fearmongering about Aids spreading among sexed-up western youth was a pack of lies.

Much of the media has treated Dr De Cock's admission as a startling revelation. In truth, experts have known for many years that in the vast majority of the world, Aids has little impact on the "general population". In her new book The Wisdom of Whores, Elizabeth Pisani – who worked for 10 years in what she refers to as "the Aids bureaucracy" – admits that by 1998 it was clear that "HIV wasn't going to rage through the billions in the 'general population', and we knew it".

Some people knew it earlier. In 1987, my friend and colleague Dr Michael Fitzpatrick wrote a fiery pamphlet titled The Truth About the Aids Panic. At the height of the Conservative government's scary tombstone campaign ("Don't die of ignorance"), he wrote: "There is no good evidence that Aids is likely to spread rapidly in the West among heterosexuals." In Britain, most of the small-scale spread of "heterosexual Aids" has been a result of infected individuals arriving from Africa. In the UK in the whole of the 1980s – the decade of the Great Aids Panic – there were 20 cases of HIV acquired through heterosexual contact with an individual infected in Europe.

And it isn't the case that the heterosexual pandemic failed to materialise because officialdom's omnipresent pro-condom propaganda was a success. According to James Chin, a clinical professor of epidemiology at the University of California at Berkeley and author of the new book The Aids Pandemic, it was always a "glorious myth" that there would be an "HIV epidemic in general populations". That myth was the product of "misunderstanding or deliberate distortions of HIV epidemiology" by Unaids and other Aids activists, says Chin.

It is time to recognise that the Aids scare was one of the most distorted, duplicitous and cynical public health panics of the past 30 years. Instead of being treated as a sexually transmitted disease that affected certain high-risk communities, and which should be vociferously tackled by the medical authorities, the "war against Aids" was turned into moral crusade.

Both Conservative and New Labour governments exploited the disease to create a new moral framework for society. Through baseless fearmongering, officials sought to police and regulate the behaviour of the public. No longer able to appeal to outdated Victorian ideals of chastity or restraint, the powers-that-be used the spectre of an Aids calamity to terrify us into behaving "responsibly" in sexual and social matters.

They were aided and abetted by the rump of the radical left. Gay rights campaigners, feminists and left-leaning health and social workers stood shoulder-to-shoulder, first with the Tories and later with Labour, in spreading the "glorious myth" of a possible future Aids pandemic. An unholy alliance of old-style, prudish conservatives and post-radical, lifestyle-obsessed leftists latched on to Aids as a disease that might provide them with a sense of moral purpose.

And they ruthlessly sought to silence anyone who questioned them. Those who challenged the idea that Aids would devour sexually promiscuous young people and transform once-civilised western societies into diseased dystopias were denounced as "Aids deniers" and "heretics". Anyone who suggested that homosexuals were at greater risk than heterosexuals – and therefore the focus of government funding and, where necessary, medical assistance should be in gay communities – was denounced as homophobic. Nothing could be allowed to stand in the way of the glorious moral effort to make everyone submit to the sexual and moral conformism of the Aids crusaders.

Even in Africa – where there is a serious and deadly Aids crisis in some countries – the international focus on Aids has been motivated more by pernicious moralism than straightforward charity. Diseases such as malaria and tuberculosis are bigger killers than Aids. Yet focusing on Aids allows western governments and NGOs to lecture Africans about their morality and personal behaviour. It also adds a new gloss to the misanthropic population-control arguments of western charities, which now present their promotion of condoms in "overly fecund" Africa as a means of preventing the spread of disease.

The relentless politicisation and moralisation of Aids has not only distorted public understanding of the disease and generated unnecessary fear and angst – it has also potentially cost lives. James Chin estimates that UNAIDS wastes around $1bn a year in activities such as "raising awareness" about Aids and preventing the emergence of the disease in communities that are at little risk. How many lives could that kind of money save, if it were used to develop drugs and deliver them to infected or at-risk communities? It is time people treated Aids as a normal disease, rather than as an opportunity for spreading their own moral agendas.